Neuroblastoma (NB) is the most common extracranial malignant solid tumor in children. High-risk NB remains an incurable disease. Since recurrent somatic mutations in NB occur with relative paucity, dysregulation of oncogenic signal transduction may contribute to NB tumorigenesis. This proposal will pursue that goal by defining the role of CaM kinase-like vesicle-associated (CAMKV) in NB development and examining the therapeutic potential of CAMKV kinase inhibition for treating NB in mouse models. In our preliminary studies, we have found that CAMKV, structurally a member of the calcium/calmodulin-dependent protein kinase family, is quite specifically overexpressed in NB tumor samples, and its high expression predicts poor patient outcome. Furthermore, CAMKV acts as an active CREB kinase in NB cells. Knockdown of CAMKV expression caused a cell proliferation defect and decreased phospho-CREB level in the NB cell lines tested. In addition, we identified K252a and OTSSP167 as CAMKV inhibitors that potently inhibited cell proliferation of several NB cell lines in culture and tumor growth in the xenograft mouse model. Interestingly, our recently generated Camkv knockout mice are viable and fertile. Our long term goal is to develop novel targeted therapies for children with high-risk NB. The objective of this application is to understand the role of CAMKV in NB tumor development and demonstrate the utility of CAMKV as a biomarker and kinase target for NB therapy.The central hypothesis of this work is that CAMKV plays an important role in NB development and is a molecular kinase target in NB. The proposed experiments will test this hypothesis by dissecting the function of CAMKV signaling in NB cells and determining the effect of CAMKV inhibition on NB tumor growth in xenograft mouse models. We will also use recently generated Camkv knockout mice to define the role of CAMKV in NB development in the Th-MYCN transgenic mouse model. The specific aims for this project are: 1) To determine the mechanism of CAMKV regulation and function in NB cells; 2) To determine the role of CAMKV in NB development in tumor mouse models; 3) To determine the therapeutic potential of CAMKV inhibition in vivo. This contribution is significant because it will demonstrate the critical role of CAMKV kinase in NB development and prove that CAMKV kinase inhibition is a potential strategy to treat NB and overcome chemotherapy resistance in vivo. Furthermore, uncovering the regulation of CAMKV kinase signaling will generate a blueprint for CAMKV-based design of treatment for refractory high-risk NB. The proposed research is innovative since it is the first study to specifically uncover and target the CAMKV signaling for designing NB therapeutics and to specifically study CAMKV inhibition by small molecule inhibitors as a mechanism for overcoming chemotherapy resistance. This project will firmly establish CAMKV- based therapy as a novel therapeutic strategy for refractory high-risk NB.